METAL-SEMICONDUCTOR Si, GaAs INTERFACES

Abstract : The FN plots for Si tips are classified into lines and curves depending on the thickness of the surface oxide film, but the FN plots for a GaAs tip shows only straight lines. A double peak structure in the energy distribution curve has been observed on the field desorbed surface at medium field after deposition of 1-2 ML of Al onto a Si surface. However, with increasing the amount of deposition of Al to 3 ML on the Si surface, the double peaks disappear completely. This result suggests that the surface layers are perfectly metallized even at room temperature. An oxide film, thinner than that on a Si surface, formed on the GaAs surface and the surface composite atoms of GaAs can easily be desorbed by field desorption. An intrinsic potential drop disappears suddenly at a certain field, that is, the surface region of the field desorbed tip is composed of metallic species.